JEE Main On 08 April 2018 Question 19
Question: When metal M is treated with NaOH, a white gelatinous precipitate X is obtained, which is soluble in excess of $ NaOH $ Compound X when heated strongly gives an oxide which is used in chromatography as an adsorbent. The metal M is: [JEE Main Online 08-04-2018]
Options:
A) Al
B) Fe
C) Zn
D) Ca
Show Answer
Answer:
Correct Answer: A
Solution:
According to given question
$ \text{Al(s)+NaOH(aq)}\xrightarrow{{}}\underset{\begin{smallmatrix} \text{ White} \\ gelatinousppt \end{smallmatrix}}{\overset{\text{(X)}}{\mathop{\text{Al(OH}{{)}_3}}}},\downarrow \xrightarrow{\text{Excess NaOH}}\underset{Soluble}{\mathop{\text{Na }[\text{ Al(OH}{{)}_4}]}}, $ Compound $ \text{(X)}\xrightarrow{{}}\text{Al(OH}{{)}_3} $
on heating gives $ A{l_2}{O_3} $ which is used in chromatography as an adsorbent. Thus metal M is aluminium (Al).
